Python Script to compare two conda environments

conda_compare.py

#!/usr/bin/env python2

"""
quicky script that compares two conda environments

can be handy for debugging differences between two environments

This could be made much cleaner and more flexible -- but it does the job.

Please let me know if you extend or improve it.

AUTHOR: Christopher H. Barker [email protected]
LICENSE: Public domain -- do with it what you will
(But it would be nice to give me credit if it helps you)
"""

import sys
import subprocess


def get_env_list(env_name):
    cmd = "conda list -n " + env_name
    print cmd
    pkg_list = subprocess.check_output(cmd, shell=True)
    # process the package list
    pkgs = {}
    for line in pkg_list.split('\n'):
        line = line.strip()
        if not line or line[0] == '#':
            continue
        parts = line.split()
        pkg, version, build = parts[:3]
        if build == '<pip>':
            channel = "pip"
        else:
            channel = "defaults" if len(parts) < 4 else parts[3]
        pkgs[pkg] = (version, build, channel)

    return pkgs


def compare_envs(env1, env2):
    pkgs1 = set(env1)
    pkgs2 = set(env2)

    in_both = pkgs1 & pkgs2
    in_one = (pkgs1 ^ pkgs2) & pkgs1
    in_two = (pkgs1 ^ pkgs2) & pkgs2

    diff_version = []
    same_version = []
    for pkg in in_both:
        if env1[pkg] != env2[pkg]:
            diff_version.append(pkg)
        else:
            same_version.append(pkg)

    return in_one, in_two, diff_version, same_version


def print_report(env, pkgs):
    for pkg in pkgs:
        print "{:25}{:10}{:20}{:20}".format(pkg, *env[pkg])


def print_diff_version(name1, env1, name2, env2, pkgs):
    print "Packages in both, with differnt versions:"
    #print "     {:15}{:10}{:20}{:20}".format("
    for pkg in pkgs:
        print pkg, ":"
        print "    {:15}{:10}{:20}{:20}".format(name1, *env1[pkg])
        print "    {:15}{:10}{:20}{:20}".format(name2, *env2[pkg])


if __name__ == "__main__":
    try:
        env1 = sys.argv[1]
        env2 = sys.argv[2]
    except IndexError:
        print "you need to pass the name of two environments at the commmand line"

    e1 = get_env_list(env1)
    e2 = get_env_list(env2)
    in_one, in_two, diff_version, same_version = compare_envs(e1, e2)

    print "In only", env1
    print_report(e1, in_one)

    print "\nIn only", env2
    print_report(e2, in_two)

    print "\nIn both, same version:"
    print_report(e1, same_version)

    print
    print_diff_version(env1, e1, env2, e2, diff_version)

I made a Python 3 version if anyone is interested. Thank you @ChrisBarker-NOAA! I found this to be quite helpful.